Emotionally detached and socially isolated, Kang-do's daily life is a succession of brutally violent incidents. As a feared and infamous debt collector on the streets of South Korea, he is renowned for his horrifically sadistic methods and his merciless, cold bloodied disregard for human life. That is until he meets a mysterious woman who claims to be the mother that abandoned him at birth. Initially sceptical, he eventually lets her into his life, only for her to suddenly vanish. On the hunt for the culprits he believes are responsible for her disappearance, Kang-do is thrown into a dark and savage journey of fatal secrets that will take him to the edge of sanity.